The purpose is to obtain preliminary information about the safety and efficacy of intravenous immune globulin (IVIG) in treating polyarticular JRA (poly-JRA). A multi-centered, phase I/II blinded-withdrawal design was used in which all patients who entered the trial received an infusion of open-label IVIG bimonthly for the first 2 months, then monthly for up to 6 months. About 75% of the patients with poly-JRA have shown "important clinical benefit" on IVIG.